Roseomonas, recently described genus of gram-negative coccobacilli, was formerly designated as "pink coccoid group" by the National Communicable Disease Center because of the organism's characteristic pink colonies. Since 1991 we have isolated Roseomonas from eight patients; seven from blood cultures and one from a skin lesion. The seven blood isolates were from patients with significant underlying diseases and central venous catheters. Our findings indicated that this organism causes central venous catheter-associated bacteremia in immunocompromised patients. Patients were predominantly female (5/7) and had solid tumors (5/7); one patient was in end-stage HIV disease. Five had fever as the primary basis for obtaining blood cultures, while another had catheter site tenderness. Four of the seven had mixed organism infections. The isolates had originally been identified by us as NCDC pink coccoid Group III. Using the newly proposed criteria for this genus, we determined that all of our eight isolates were consistent with Roseomonas gilardii. To determine whether we were dealing with the same strain of organism, indicative of a common source, we attempted to type these isolates using molecular typing procedures. Although pulsed-field gel electrophoresis (PFGE) patterns could be obtained using restriction enzymes SpeI + Xba1, this method was quite labor-intensive and not sufficiently discriminatory. More definitive results were obtained using a random amplified polymorphic DNA (RAPD) technique, which showed that each of the eight isolates had distinctly different RAPD patterns. RAPD is faster and simpler to perform than PFGE and is the method of choice for determining Roseomonas.